The Democrats' position on the Iraq War has been a muddle. Many top Democrats supported it, although it's hard to believe all of them had their hearts in it. Of course, the party's core supporters were passionately opposed from the beginning. This has led to the Democrats' pull-out, no-don't-pull-out, please-don't-ask-us-what-we-think pile of contradictions and evasions on the war.

The muddle is moving toward a resolution, and the vehicle for it is next month's Democratic Senate primary race in Connecticut. Sen. Joe Lieberman has been a stalwart supporter of the war, and the left-wing blogosphere — representing the party's mad-as-hell anti-war base — has resolved to make him pay. Anti-war challenger Ned Lamont is such a threat to Lieberman that the three-term incumbent and former vice-presidential candidate is preparing to run as an independent in the general election, should he lose the primary.

A Lieberman loss could signal a turning point as significant, in its way, as the rise in the GOP of the Goldwaterites, who vanquished the liberal Rockefeller Republicans, or the ascendancy of the McGovernites, who sent the old hawkish Scoop Jackson Democrats packing. Unfortunately, there aren't many Lieberman-style hawks left in the party to begin with, which is Lieberman's problem.

After the 2004 election, then-New Republic editor Peter Beinart wrote an influential article calling on liberal hawks basically to purge the anti-war zealots from the party. Instead, the anti-war zealots are conducting a purge of the liberal hawks, and why not? They are a majority within the party, and events have done more to vindicate than to discredit their opposition to the Iraq War — so much so that even erstwhile purger Beinart has called his support for it a mistake.

As the poet once said, you don't have to be a weatherman to tell which way the wind is blowing. You only have to be a weather-vane politician sticking his (or her) finger in the wind. John Edwards has repudiated the war and lurched left since his 2004 vice-presidential run. He leads in presidential polls in Iowa. John Kerry regrets his prior support of the war and wants a deadline, any deadline, for exiting Iraq. Even the cautious Hillary Clinton just turned her back on Lieberman by saying she would support Lamont if he wins the primary.

If Lieberman does lose, it will be a sign that Clinton herself is vulnerable to a challenge from the left in the 2008 presidential primaries. Then, she will be under enormous pressure to walk away from her support of the war, too.

The biggest winner is Howard Dean, left for dead after his infamous 2004 Iowa "scream." Lamont is a straight Deaniac, not just in his opposition to the war, but in his demographic profile: white, well-off and highly educated. These are the same people who backed the successful peacenik insurrection of George McGovern in 1972, and now they are bidding to make their control of their party all the more complete. Democratic commentator Marshall Wittmann calls the left-wing bloggers "McGovernites with modems."

Their main issue is the war, but they also represent a general repudiation of the one hiccup in the post-1972 McGovernite dominance of the party, the Clinton administration circa 1994-1998. Clinton was pro-growth, pro-free trade, tonally moderate and willing to use force abroad. Al Gore spurned this winning centrist formula in 2000, but he felt compelled to make a bow to it by picking the moderate Lieberman as his running mate. Now, the Democratic party is on the verge of saying a Lieberman-style hawkish-centrism is utterly anathema.

Lieberman could still win the primary. Even if he loses, he could win the general election as an independent, showing that the party's left wing doesn't have wider appeal. But if Lieberman is ousted from his seat, it will be a decisive victory for the party's haters and anti-war bloggers. The Democrats' muddle on Iraq will finally have ended, and the party will be the poorer for it.